Cameron has complained in the years since "Avatar" about how schlocky 3D conversions erode the format — especially when studios take control from directors. Unlike films shot in 3D, he says conversions do not portray the same visual depth.

“One thing is shooting in 3D and another is to convert to 3D,” he said.

Ironically, Cameron converted "Titanic" to 3D last year … but justified that by noting at length how hands-on he was in the conversion process.

Cameron also confirmed at TagDF that he will begin development of "Battle Angel" in 2017, following the "Avatar" sequels.